The present invention relates to a radial artery compression system, and more particularly to an adjustable radial artery compressor, with which the compression force applied on the radial artery can be adjusted so that haemostasis can be obtained without occluding the artery. Further, when arranged around the forearm of a patient, the present radial artery compressor ensures that the same compression pressure is applied on the radial artery irrespectively of the position of the forearm, which reduces the immobility time for the patient.
Following an invasive medical procedure, such as catheterisation or similar invasive medical procedure, the flow of blood through the puncture wound has to be stopped, so that haemostasis can begin as soon and fast as possible after the completion of the invasive medical procedure. Several devices have been suggested that facilitate and accelerate this haemostasis by providing a compression pressure that compresses blood vessels in various parts of the body to stop flow of blood therethrough.
In the case of radial artery catheterisation, several radial artery occluders have been developed that stop the flow of blood through the puncture wound in the wrist by applying a compression force that occludes the radial artery. An illustrative example of such a pressure-applying device is disclosed in U.S. Pat. No. 5,601,597. This known artery occluder comprises a wrist splint, an adjustable securing strap attached to one end of the splint, and an adjustable pressure strap attached to other end of the splint and provided with a pressure pad. When the artery occluder is mounted around the forearm of a patient, the wrist splint extends along the distal end of the forearm and the back of the wrist and hand, the securing strap extends around the palm of the hand, and the pressure strap extends around the distal end of the forearm, with the pressure pad being positioned over the puncture wound in the radial artery. During use of this occluder, the adjustable pressure strap is slowly tightened over the bleeding wound in the radial artery until the flow of blood in the radial artery has stopped at the wound. This aids haemostasis in the wound, but allows the ulnar artery to deliver enough blood to ensure tissue viability. In addition, the adjustable securing strap is tightened around the palm of the hand to immobilize the wrist.
In U.S. Pat. No. 5,601,597 the inventors emphasize on the importance of immobilizing the wrist joint since movement of the wrist may cause stretching and contraction of the wounded tissue. Stretching and contraction of the tissue surrounding the puncture wound can prevent clotting and thereby causing delay in haemostasis of an arterial puncture. However, although the device according to U.S. Pat. No. 5,601,597 effectively prevents a patient from bending his/her wrist, it is still relatively easy for the patient to twist the forearm, i.e. to rotate the hand. As will be described below, when the forearm is twisted, the two bones in the forearm, the ulnar bone and the radius bone, will cross over. Since the device above stops the flow of blood through the radial artery by compressing the radial artery between the pressure pad and the radius bone, this cross-over of the ulnar and radius bones will change the magnitude of the compression force on the radial artery and may also change the position of the radial artery itself. Consequently, a twist of the forearm may delay the haemostasis process and even cause more severe problems, such as reopening of the puncture wound. In practise, the patient is therefore immobilized during the compression period, i.e. the time for the haemostasis to occur.
Another disadvantage with the device according to U.S. Pat. No. 5,601,597, and also with similar devices that are mounted around the wrist and forearm so that the forearm is surrounded by a strap and/or a splint, arises from the fact that the compression force applied on the radial artery, i.e. the force on the underside of the forearm, equals the force applied on the upside of the forearm. Due to the superficial location of the veins at the upside of the forearm, this type of design may lead to vein stasis. Vein stasis for a longer period can be both painful for the patient and cause vein thrombosis. As is done in U.S. Pat. No. 5,601,597, this problem can be reduced by letting a splint or support plate distribute the reaction force onto the upside of the forearm over a large area, thereby reducing the compression pressure on the veins. However, since the compression device normally remains seated over the puncture wound for several hours, the flow of blood through the veins is still restricted for a long time period, and the risk of vein stasis is therefore not completely eliminated.
In the vast majority of prior art designs in which the compression force is applied by straps that are secured in tension by buckles or Velcro, it is very difficult to fine-tune the compression pressure. In use, this means that such a compression device is arranged around the wrist and forearm of a patient and is then left untouched in this position for the whole compression period, i.e. the same compression pressure is applied during the whole compression period. However, since it is known that a higher compression pressure is required in the beginning of the compression period than in the end of the compression period, this procedure is not ideal. Without the possibility to fine-tune the compression pressure, it is also difficult to accommodate individual differences among different patients, i.e. there is a risk that a higher compression pressure than needed is applied on the puncture wound, which increases the risk of vein stasis.
Finally, as mentioned above, when the radial artery is occluded, only the ulnar artery delivers blood to the hand. Although the ulnar artery alone normally is capable of deliver enough blood to the hand to ensure tissue viability, obviously it would be advantageous if the compression pressure could be fine-tuned in such a way that haemostasis is obtained without occluding the radial artery completely.
An improved radial artery compressor is needed, which overcomes the disadvantages of the prior art devices.
A first object of the present invention is therefore to provide an adjustable radial artery compressor that provides a possibility to fine-tune the compression pressure over the puncture wound following an invasive medical procedure such as catheterisation.
A second object of the present invention is to provide a radial artery compressor with which the compression pressure applied over the puncture wound is constant irrespective of any movements of the hand or forearm.
A third object of the present invention is to provide a radial artery compressor that eliminates or minimizes the risk of vein stasis in the superficial veins at the upside of the forearm.
These objects are achieved with an adjustable radial artery compressor as defined in claim 1. Preferred embodiments of the adjustable radial artery compressor according to the invention are defined in the dependent claims.
An embodiment of the adjustable radial artery compressor according to the present invention includes basically two arms, a support arm and a compression arm, which form a C-shaped clamp. The support arm and the compression arm are pivotally connected in a hinge joint in such way that the support arm extends behind the compression arm. In the opposite ends, i.e., the ends remote from the hinge joint, the support and compression arms are each provided with a pad. A clamping screw is threaded through the end of the extending support arm and is in contact with the compression arm. When the clamping screw is turned inwards, it presses against the compression arm, thereby controlling the distance between the compression pad on the compression arm and the support pad on the support arm. In use, the forearm of a patient is arranged between the compression pad on the compression arm and the support pad on the support arm so that the radial artery is compressed between the radius bone and the compression pad. By turning the clamping screw inwards or outwards, it is therefore possible to adjust the compression pressure on the radial artery with high precision.